This invention relates to chipper apparatus, and more particularly to what is referred to herein as a drum-type chipper, which includes a power-driven rotatable drum, and multiple blades or knives distributed about the periphery of the drum for cutting material into chips with rotation of the drum. The particular embodiment of the invention described herein is a drum brush chipper, which includes a drum with knives and the knives are rotated with rotation of the drum in circular sweeps past an adjacent cutter bar to produce chips from material. Typically, a brush chipper may be part of a movable vehicle, such as a towed trailer, and used by the operator to cut up brush, limbs, and other residues into chips for easy disposal.
For a chipper to operate properly, it is important that the cutting edges of the knives that produce the chips be sharp, and that these knives be precisely located on the drum of the chipper so as to protrude the exact required distance beyond the surface of the chipper drum. With a brush chipper which includes a cutter bar, which the cutting edges move adjacent during the chipping action, exact positioning of the knives results in the precise clearance desired between the cutting edges and the cutter bar to produce optimum chipping. In a conventional chipper, to produce a sharp cutting edge, a knife is removed from the chipper drum, sharpened, and then returned. Sharpening of a knife changes the location of the cutting edge with respect to the body of the knife. This requires that each knife that is removed from the chipper drum, and after sharpening, be remounted with care taken that the knife be repositioned to have the desired clearance. When it is remembered that most chipper drums have multiple knives, it becomes obvious that sharpening of knife edges, in addition to requiring skill and exactitude in the operator, is time-consuming, and is reflected in labor costs and down time in the chipper.
A general object of the invention is to provide an improved drum-type chipper with a unique construction for supporting a knife which facilitates replacement of an edge when needed.
Another object is to provide a chipper where the cutting edge in a knife is one of the edges of a precision-made, replaceable, double-edged knife. With dulling of an edge, a new edge is provided, either by turning over the knife to put its other edge in a cutting position, or by replacing the knife if both edges have been dulled.
Yet a further object is to provide a chipper which includes a knife mounting for supporting the knife with the knife mounting having means for precisely locating a knife, with respect to the mounting, and with the chipper drum which mounts the knife mounting having means which precisely locates the knife mounting on the drum.
With the organization described, a knife may be replaced, with the replacing knife having a cutting edge which is precisely located at a desired position, without the necessity of producing adjustments in the machine each time a replacement occurs.